A computer network or data network is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices exchange data with each other using a data link. The connections between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.
Network computer devices that originate, route, and terminate the data are called network nodes. Nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices can be said to be networked together when one device is able to exchange information with the other device, whether or not they have a direct connection to each other. Computer networks differ in the transmission medium used to carry their signals, the communications protocols to organize network traffic, the network's size, topology, and organizational intent.
An enterprise fabric network may use a network overlay, which is a virtual network of interconnected nodes that share an underlying physical network. Examples of network overlays include Virtual Extensible LAN (VXLAN), Network Virtualization Using Generic Routing Encapsulation (NVGRE), Transparent Interconnection of Lots of Links (TRILL), and Location/Identifier Separation Protocol (LISP). LISP is a network architecture and a set of protocols that creates two namespaces and uses two IP addresses: Endpoint Identifiers (EIDs), which are assigned to end-hosts, and Routing Locators (RLOCs), which are assigned to network devices (e.g., routers) that make up the underlay routing system.